In general, obesity refers to a condition of excess accumulation of fatty tissue in the body. Body mass index (BMI), which is adopted in a health check up, etc., is determined by dividing body weight (kg) by the square of height (m). Body weight for which BMI is 22 is referred to as standard body weight, and a body weight that is 10% or more higher than the standard body weight is referred to as being overweight, while a body weight that is 20% or more higher than the standard body weight is referred to as obesity. The number of obese persons and persons who would become obese has increased in recent years due to Westernization of the diet, a lack of exercise resulting from the development of transportation facilities and the like. In particular, obesity is closely correlated with the onset of diseases such as hypertension, diabetes, fatty liver, arteriosclerosis, stroke, hyperlipemia, peripheral circulatory disorders and ischemic heart disease, and the prevention or decrease of obesity is extremely important from the viewpoint of preventing and treating the onset of these diseases.
Although improvement of lifestyle in terms of diet therapy and exercise therapy is desirable for preventing or decreasing obesity, this cannot always be easily achieved. In addition, although drug therapy is available for the treatment of obesity, including the use of lipid absorption inhibitors and intestinal absorption inhibitors, their use is limited to cases of serious obesity.
Amidst these circumstances, various products using natural ingredients having various actions and having less potential for adverse side effects and the like even if taken for a long period have been sold commercially in the form of a diet food and the like for the purpose of preventing or decreasing obesity, and searches are being made for novel substances having an anti-obesity activity.
For example, Patent Document 1 discloses that a dried powder, extract or purified product of Kouki leaves or bark has a weight loss effect on rats and humans. In addition, Patent Document 2 discloses that tannin, a kind of polyphenol has α-amylase inhibitory effects and anti-obesity effects.
On the other hand, with respect to acacia acacia honey is known, and tannin which is extracted from bark thereof is known to be able to be used as a tanning agent or a wood adhesive, while more recently, extracts of genus Acacia have been disclosed to have selective inhibitory effects on COX-2 (Patent Document 3), and bark of genus Acacia has been disclosed to have active oxygen eliminating effects (Patent Document 4) and skin whitening effects due to the effect of inhibiting tyrosinase activity (Patent Document 5). However, acacia bark and polyphenols derived from acacia bark have heretofore not been known to have an anti-obesity action.
[Patent Document 1] JP2004-091464A
[Patent Document 2] JP2002-051735A
[Patent Document 3] JP2004-532811A
[Patent Document 4] JP2004-352639A
[Patent Document 5] JP10-025238A